1. Field of the Invention
The present invention relates to an improvement in an automatic control system for a well pump installation and, more particularly, to a water pressure system to be incorporated in the automatic control system.
2. Description of the Prior Art
Conventionally, a well pump installation with an automatic control system is equipped with a dry cut-off relay adapted to stop a pump motor in case of a dry operation of the pump which may be incurred by, for example, an invasion of air through a deteriorated junction of a suction pipe, thereby to prevent burning of the pump motor and other troubles which may be incurred by the dry operation of the pump.
Since the conventional dry cut-off relay is so constructed as to stop the pump motor relying solely upon the suction head (usually, a negative pressure), the cut-off relay tends to erroneously operate to stop the pump motor when the normal water level in the well is extremely high or when the pump is installed beneath the normal water level.